Calibration method and device for an imaging device and imaging device

Abstract

A calibration procedure and calibration device for an imaging device, as well as an imaging device itself, are provided, which may be applicable in the fields of safety engineering and medical diagnostics. The procedure comprises: calculating (S210) a first theoretical line of intersection according to a theoretical target point position of a radiation source of the imaging device, a theoretical detection position of a detector, and a phantom position of a calibration phantom; determining (S220) first detection projection information for the calibration phantom based on the first theoretical line of intersection, an attenuation coefficient of radiation emitted by the radiation source in the calibration phantom, and a radiation energy spectrum distribution of the radiation source in the imaging device;and adjusting (S230) a parameter of the imaging device using difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom with the imaging device to calibrate the imaging device and obtain a calibrated target parameter.

Description

Calibration method and device for imaging device, and imaging device Technical Field

[0001] At least one embodiment of the present disclosure relates to an imaging device, and in particular to a calibration method and apparatus for an imaging device, and an imaging device. Background Art

[0002] In recent years, X-ray computed tomography (CT) technology has been widely used in technical fields such as industrial inspection, medical diagnosis, and security inspection. CT imaging devices based on CT technology can scan objects or the human body to obtain image information of their internal structures. However, due to equipment assembly errors, equipment aging, and other factors, geometric errors may occur in CT imaging equipment components such as the light source and detector. This can lead to image distortion, ring artifacts, and other image defects in the image information reconstructed by the CT imaging device, thereby reducing the imaging quality of the reconstructed image information.

[0003] CT imaging equipment is often calibrated to improve image reconstruction. However, calibration methods are inefficient and often produce images with numerous defects.

[0004] Summary of the Invention

[0005] In view of the above problems, the present disclosure provides a calibration method, apparatus, and imaging device for an imaging device.

[0006] According to a first aspect of the present disclosure, a calibration method for an imaging device is provided, comprising:

[0007] Calculating a first theoretical intersection line based on the target theoretical position of the radiation source of the imaging device, the detection theoretical position of the detector, and the phantom position of the calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after a connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom;

[0008] Determining first detection projection information for the calibration phantom based on the first theoretical intersection line, the attenuation coefficient of the radiation emitted by the radiation source in the calibration phantom, and the energy spectrum distribution of the radiation source in the imaging device; and

[0009] The parameters of the imaging device are adjusted using the difference information between the first detection projection information and the second detection projection information obtained by the imaging device scanning the calibration phantom, so as to calibrate the imaging device and obtain the calibrated target parameters.

[0010] According to an embodiment of the present disclosure, adjusting the parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by the imaging device scanning the calibration phantom includes:

[0011] The target parameters are obtained by processing the difference information between the first detection projection information and the second detection projection information according to the objective function, wherein the target difference information between the target second detection projection information obtained after scanning the calibration phantom by the imaging device calibrated according to the target parameters and the first detection projection information converges.

[0012] According to an embodiment of the present disclosure, the objective function includes a mapping function and a loss function;

[0013] Processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameters includes:

[0014] Using the mapping function to process the first detection projection information and the second detection projection information respectively, to obtain a first projection mapping value and a second projection mapping value;

[0015] Processing the first projection mapping value and the second projection mapping value using the loss function to obtain a loss value;

[0016] Iteratively adjusting parameters of the imaging device according to the loss value until the loss function converges; and

[0017] The parameters corresponding to the convergence of the above loss function are determined as the above target parameters.

[0018] According to an embodiment of the present disclosure, the imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2;

[0019] Adjusting parameters of the imaging device using the first detection projection information and difference information between the second detection projection information obtained by scanning the calibration phantom with the imaging device includes:

[0020] Adjusting device imaging parameters of each of the scanning-stage imaging devices based on difference information between the second detection projection information obtained by scanning the calibration object by each of the scanning-stage imaging devices and the first detection projection information corresponding to each of the scanning-stage imaging devices to obtain calibrated target device imaging parameters of each of the scanning-stage imaging devices; and

[0021] The target device imaging parameters of each of the L scanning-stage imaging devices are calibrated into a coordinate system to obtain calibrated target parameters.

[0022] According to an embodiment of the present disclosure, the calibration phantom is set in N different calibration areas, N ≥ 2;

[0023] The above calibration method also includes:

[0024] Scanning the calibration phantom in each calibration area using the imaging device to obtain candidate second detection projection information corresponding to each calibration area; and

[0025] The second detection projection information is determined according to the candidate second detection projection information corresponding to each of the N marked areas.

[0026] According to an embodiment of the present disclosure, the calibration phantom is set in a calibration area, and the calibration phantom set in the calibration area includes M calibration postures, M≥2;

[0027] The imaging device calibration method further includes:

[0028] Scanning each calibration phantom of the calibration posture using the imaging device to obtain candidate second detection projection information corresponding to the calibration phantom and each calibration posture; and

[0029] The second detection projection information is determined according to the candidate second detection projection information corresponding to each of the M calibration postures.

[0030] According to an embodiment of the present disclosure, the calibration phantom is disposed in a scanning area of ​​the imaging device; and

[0031] The coverage area of ​​the calibration phantom covering the scanning region is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning region area of ​​the scanning region.

[0032] According to an embodiment of the present disclosure, the calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

[0033] According to an embodiment of the present disclosure, the calibration wire includes at least one of the following:

[0034] Cylindrical calibration wire, cubic calibration wire, conical calibration wire, trapezoidal calibration wire.

[0035] According to an embodiment of the present disclosure, the parameters of the imaging device include:

[0036] The target position of the radiation source and the detection position of the detector.

[0037] A second aspect of the present disclosure provides a calibration device for an imaging device, comprising:

[0038] a calculation module configured to calculate a first theoretical intersection line based on a target theoretical position of the radiation source of the imaging device, a detection theoretical position of the detector, and a phantom position of the calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after a connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom;

[0039] a determination module configured to determine first detection projection information for the calibration phantom based on the first theoretical intersection line, the attenuation coefficient of the radiation emitted by the radiation source in the calibration phantom, and the energy spectrum distribution of the radiation source in the imaging device; and

[0040] The adjustment module is configured to adjust the parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by the imaging device scanning the calibration model, so as to calibrate the imaging device and obtain the calibrated target parameters.

[0041] According to an embodiment of the present disclosure, the adjustment module is further configured to:

[0042] The target parameters are obtained by processing the difference information between the first detection projection information and the second detection projection information according to the objective function, wherein the target difference information between the target second detection projection information obtained after scanning the calibration phantom by the imaging device calibrated according to the target parameters and the first detection projection information converges.

[0043] According to an embodiment of the present disclosure, the objective function includes a mapping function and a loss function;

[0044] Processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameters includes:

[0045] Using the mapping function to process the first detection projection information and the second detection projection information respectively, to obtain a first projection mapping value and a second projection mapping value;

[0046] Processing the first projection mapping value and the second projection mapping value using the loss function to obtain a loss value;

[0047] Iteratively adjusting parameters of the imaging device according to the loss value until the loss function converges; and

[0048] The parameters corresponding to the convergence of the above loss function are determined as the above target parameters.

[0049] According to an embodiment of the present disclosure, the imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2;

[0050] The above adjustment module is further configured to:

[0051] Adjusting device imaging parameters of each of the scanning-stage imaging devices based on difference information between the second detection projection information obtained by scanning the calibration object by each of the scanning-stage imaging devices and the first detection projection information corresponding to each of the scanning-stage imaging devices to obtain calibrated target device imaging parameters of each of the scanning-stage imaging devices; and

[0052] The target device imaging parameters of each of the L scanning-stage imaging devices are calibrated into a coordinate system to obtain calibrated target parameters.

[0053] According to an embodiment of the present disclosure, the calibration phantom is set in N different calibration areas, N ≥ 2;

[0054] The calibration device further includes:

[0055] a first scanning module, configured to scan the calibration phantom in each calibration area using the imaging device to obtain second detection projection information corresponding to each calibration area; and

[0056] The first determining module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the N calibration areas.

[0057] According to an embodiment of the present disclosure, the calibration phantom is set in a calibration area, and the calibration phantom set in the calibration area includes M calibration postures;

[0058] The calibration device further includes:

[0059] A second scanning module is configured to use the imaging device to scan each calibration phantom of the calibration posture to obtain second detection projection information corresponding to the calibration phantom and each calibration posture; and

[0060] The second determination module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the M calibration postures.

[0061] According to an embodiment of the present disclosure, the calibration phantom is disposed in a scanning area of ​​the imaging device; and

[0062] The coverage area of ​​the calibration phantom covering the scanning region is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning region area of ​​the scanning region.

[0063] According to an embodiment of the present disclosure, the calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

[0064] According to an embodiment of the present disclosure, the calibration wire includes at least one of the following:

[0065] Cylindrical calibration wire, cubic calibration wire, conical calibration wire, trapezoidal calibration wire.

[0066] According to an embodiment of the present disclosure, the parameters of the imaging device include:

[0067] The target position of the radiation source and the detection position of the detector.

[0068] A third aspect of the present disclosure provides an imaging device, comprising:

[0069] a radiation source adapted to emit a radiation beam;

[0070] A conveying device, adapted to convey the inspected article, wherein a conveying channel is defined above the conveying device, and the calibration phantom is disposed in the conveying channel;

[0071] a detector adapted to receive the radiation beam that passes through the object to be inspected or the calibration phantom; and

[0072] According to the calibration device as described above.

[0073] According to the imaging device calibration method, device, and imaging device of the above-mentioned embodiment, the parameters of the imaging device can be adjusted according to the difference between the second detection projection information and the first detection projection information obtained by scanning the calibration phantom by the imaging device, so that the parameters of the imaging device corresponding to the time when the difference between the second detection projection information and the first detection projection information is minimized can be used as the target parameters, thereby completing the calibration of the system parameters of the imaging device and improving the image quality of the reconstructed image output by the CT imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0075] FIG1 schematically shows an application scenario of a calibration method and apparatus for an imaging device according to an embodiment of the present disclosure;

[0076] FIG2A schematically shows a flow chart of a calibration method for an imaging device according to an embodiment of the present disclosure;

[0077] FIG2B schematically shows a schematic diagram of a calibration unit and a calibration phantom according to an embodiment of the present disclosure;

[0078] 3A schematically shows a flow chart of processing difference information between first detection projection information and second detection projection information according to an objective function to obtain target parameters according to an embodiment of the present disclosure;

[0079] FIG3B schematically shows an application scenario diagram of a calibration method for an imaging device according to another embodiment of the present disclosure;

[0080] FIG3C schematically shows a schematic diagram of an energy spectrum distribution curve of a radiation source according to an embodiment of the present disclosure;

[0081] FIG3D schematically shows a curve diagram of changes in mass attenuation coefficient and X-ray energy of a calibration phantom according to an embodiment of the present disclosure;

[0082] FIG4 schematically illustrates a flow chart for adjusting parameters of an imaging device using first detection projection information and difference information between second detection projection information obtained by scanning a calibration phantom with an imaging device according to an embodiment of the present disclosure;

[0083] FIG5 schematically illustrates a flow chart for adjusting parameters of an imaging device using difference information between first detection projection information and second detection projection information obtained by scanning a calibration phantom with an imaging device according to another embodiment of the present disclosure;

[0084] FIG6 schematically illustrates a flow chart for adjusting parameters of an imaging device using difference information between first detection projection information and second detection projection information obtained by scanning a calibration phantom with an imaging device according to yet another embodiment of the present disclosure;

[0085] FIG7 schematically shows a structural block diagram of a calibration apparatus for an imaging device according to an embodiment of the present disclosure;

[0086] FIG8 schematically shows an application scenario diagram of an imaging device according to an embodiment of the present disclosure; and

[0087] FIG9 schematically shows a block diagram of an electronic device suitable for implementing a calibration method for an imaging device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0088] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0089] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0090] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0091] When expressions such as "at least one of A, B and C, etc." are used, they should generally be interpreted in accordance with the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0092] In the technical solution disclosed herein, the collection, storage, use, processing, transmission, provision, disclosure and application of user personal information involved comply with the provisions of relevant laws and regulations, take necessary confidentiality measures, and do not violate public order and good morals.

[0093] In the technical solution disclosed herein, the user's authorization or consent is obtained before obtaining or collecting the user's personal information.

[0094] CT imaging technology is currently widely used in many fields such as medical treatment and security inspection. Based on CT imaging technology, it can non-destructively obtain three-dimensional image information of the object being measured or the internal structure of the human body. During the CT imaging process, the geometric error of the equipment will cause the reconstructed three-dimensional image to be distorted, resulting in problems such as inaccurate CT values ​​or ring artifacts. There are many types of CT equipment currently, including the most common spiral scanning cone-beam CT and static CT, which is at the forefront of research. The former has a simple system structure, so the parameter calibration method is relatively simple, while the latter has a more complex system structure and often requires simultaneous calibration of multiple parameters. CT imaging systems usually include three major components: an X-ray machine, an imaging object, and a detector. Their respective parameters need to be adjusted to be closer to the actual values ​​in order to obtain clearer reconstructed images.

[0095] Related geometric calibration methods are primarily targeted at spiral scanning cone-beam CT devices, such as those that manually or electrically adjust the parameters of certain device components on a CT device, relying on subjective judgment or objective indicators to determine the adjustment method for the device components. Considering that the methods for adjusting device components are often time-consuming and labor-intensive, and are significantly influenced by subjective factors, consideration has been given to designing a calibration phantom with a specific structure. Then, based on the scanning imaging results of this phantom in the CT device, the corresponding system parameters are calibrated. However, other CT imaging systems, including static CT devices, have more numerous and complex system parameters, and simple geometric calibration methods often fail to achieve optimal image reconstruction results.

[0096] Adjusting CT device component parameters based on reconstructed image quality is cumbersome and highly dependent on operator expertise. It's also unsuitable for other CT imaging systems, which have more complex and diverse architectures. This approach requires human judgment on image quality, a qualitative assessment that varies from person to person and is difficult to replicate.

[0097] It should be noted that the parameters of the imaging device (or CT device) described in the embodiments of the present disclosure may include geometric parameters of the device in the related art.

[0098] An embodiment of the present disclosure provides a calibration method for an imaging device, comprising:

[0099] According to the target theoretical position of the radiation source of the imaging device, the detection theoretical position of the detector, and the phantom position of the calibration phantom, a first theoretical intersection line is calculated, wherein the first theoretical intersection line represents a propagation path formed in the calibration phantom after the connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom; based on the first theoretical intersection line, the attenuation coefficient of the ray emitted by the radiation source in the calibration phantom, and the ray energy spectrum distribution of the radiation source in the imaging device, first detection projection information for the calibration phantom is determined; and using the difference information between the first detection projection information and the second detection projection information obtained by the imaging device scanning the calibration phantom, the parameters of the imaging device are adjusted to calibrate the imaging device and obtain the calibrated target parameters.

[0100] According to an embodiment of the present disclosure, by calculating the first theoretical intersection line formed in the calibration phantom by the connecting line between the theoretical position of the target and the theoretical position of the detection, the theoretical position of the radiation passing through the calibration phantom can be determined when the target of the radiation source and the detector crystal are respectively at the theoretical positions. Therefore, the first theoretical intersection line, the attenuation coefficient of the radiation in the calibration phantom, and the energy spectrum distribution of the radiation of the radiation source can be used to calculate the first detection projection information used to characterize the situation when the target and the detection crystal are both at the theoretical positions. Then, according to the difference between the second detection projection information obtained by scanning the calibration phantom by the imaging device and the first detection projection information, the parameters of the imaging device are adjusted, thereby The parameters of the imaging device corresponding to the time when the difference between the second detection projection information and the first detection projection information is minimized can be used as the target parameters, thereby completing the calibration of the system parameters of the imaging device, and thus at least partially solving the technical problem in the related art that the operation of the imaging device calibration process is relatively cumbersome and highly dependent on the professional level of the operator. At the same time, the calibration method provided in this embodiment can be repeatedly applied to different CT imaging devices with more complex and diverse system structures. The calibration method for imaging devices provided in the embodiment of the present disclosure can achieve accurate calibration of the CT imaging device, thereby improving the image quality of the reconstructed image output by the CT imaging device.

[0101] FIG1 schematically shows an application scenario diagram of a calibration method and apparatus for an imaging device according to an embodiment of the present disclosure.

[0102] As shown in FIG. 1 , the application scenario 100 according to this embodiment may include terminal devices 101 , 102 , and 103 , a network 104 and a server 105 , as well as an imaging device 110 and a calibration phantom 121 .

[0103] The imaging device 110 may include a radiation source 111 and a detector 112 , with a calibration phantom 121 disposed between the radiation source 111 and the detector 112 .

[0104] The network 104 is used to provide a medium for communication links between the terminal devices 101, 102, 103 and the server 105. The network 104 may include various connection types, such as wired or wireless communication links or fiber optic cables.

[0105] Users can use terminal devices 101, 102, and 103 to interact with server 105 via network 104 to receive or send messages, etc. Various communication client applications can be installed on terminal devices 101, 102, and 103, such as shopping applications, web browser applications, search applications, instant messaging tools, email clients, social platform software, etc. (only as examples).

[0106] The terminal devices 101 , 102 , and 103 may be various electronic devices having a display screen and supporting web browsing, including but not limited to smart phones, tablet computers, laptop computers, and desktop computers.

[0107] The server 105 may be a server that provides various services, such as a background management server (for example only) that supports websites browsed by users using the terminal devices 101, 102, and 103. The background management server may analyze and process received data such as user requests, and feed back processing results (such as web pages, information, or data obtained or generated according to user requests) to the terminal device.

[0108] It should be noted that the calibration method for an imaging device provided in the embodiment of the present disclosure can generally be executed by the server 105. Accordingly, the calibration apparatus for an imaging device provided in the embodiment of the present disclosure can generally be set in the server 105. The calibration method for an imaging device provided in the embodiment of the present disclosure can also be executed by a server or a server cluster that is different from the server 105 and can communicate with the terminal devices 101, 102, 103 and / or the server 105. Accordingly, the calibration apparatus for an imaging device provided in the embodiment of the present disclosure can also be set in a server or a server cluster that is different from the server 105 and can communicate with the terminal devices 101, 102, 103 and / or the server 105.

[0109] It should be understood that the number of terminal devices, networks, and servers in Figure 1 is merely illustrative and any number of terminal devices, networks, and servers may be provided as required.

[0110] The following will describe in detail the calibration method of the imaging device of the disclosed embodiment based on the scenario described in FIG. 1 through FIG. 2A to FIG. 6 .

[0111] FIG2A schematically shows a flow chart of a calibration method for an imaging device according to an embodiment of the present disclosure.

[0112] As shown in FIG. 2A , the calibration method for an imaging device according to this embodiment includes operations S210 to S230 .

[0113] In operation S210, a first theoretical intersection line is calculated based on the target theoretical position of the radiation source of the imaging device, the detection theoretical position of the detector, and the phantom position of the calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after a connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom.

[0114] In operation S220 , first detection projection information for the calibration phantom is determined based on the first theoretical intersection line, the attenuation coefficient of the radiation emitted by the radiation source in the calibration phantom, and the energy spectrum distribution of the radiation source in the imaging device.

[0115] In operation S230, the parameters of the imaging device are adjusted using the difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom with the imaging device, so as to calibrate the imaging device and obtain calibrated target parameters.

[0116] According to an embodiment of the present disclosure, the imaging device may include, for example, a CT imaging device. The radiation source of the imaging device in this embodiment emits rays through a target point. The rays pass through a calibration phantom and are received by a detector. The detector may convert the received ray signal into an electrical signal, and then use the electrical signal to construct a detection image of the calibration phantom.

[0117] It should be noted that the embodiments of the present disclosure do not limit the number of radiation sources and / or detectors of the imaging device. For example, the number of radiation sources and detectors can be one, or more.

[0118] According to embodiments of the present disclosure, the theoretical target position and the theoretical detection position of the detector may be positions where the imaging device generates the optimal detection image. For example, the theoretical detection position of the detector may be the theoretical position of the detection crystal that receives the radiation signal. However, due to equipment errors, abnormal movement, and other reasons, the imaging device may cause displacement of its components, thereby reducing the image quality of the actual detection image obtained by the imaging device scanning the detection object.

[0119] According to an embodiment of the present disclosure, the first theoretical intersection line may be the coordinate position of the first theoretical intersection line in the coordinate system of the imaging device. The linear attenuation coefficient of the calibration phantom may be determined by the material from which the calibration phantom is constructed. The phantom position of the calibration phantom may be the coordinate position of the calibration phantom in the coordinate system corresponding to the imaging device, for example, the coordinate position of each particle size unit of the calibration phantom.

[0120] It should be noted that the material of the calibration phantom can be a single substance (such as aluminum), a single compound (such as PMMA) or a mixture (such as ceramics, etc.). The embodiments of the present disclosure do not limit the material of the calibration phantom, as long as the attenuation coefficient of the radiation in the calibration phantom can be obtained based on the material of the calibration phantom.

[0121] According to the embodiments of the present disclosure, the attenuation coefficient may include parameters used in related technologies to characterize the attenuation of rays in a calibration model, such as a linear attenuation coefficient or a mass attenuation coefficient. The embodiments of the present disclosure do not limit the specific type of the attenuation coefficient, and those skilled in the art may select it according to actual needs.

[0122] According to embodiments of the present disclosure, the radiation energy spectrum distribution of a radiation source in an imaging device may include a radiation energy spectrum distribution curve. This distribution curve can be obtained using measurement methods known in the relevant art. For example, assuming that the same radiation source maintains a consistent energy spectrum distribution under the same operating voltage conditions, the radiation energy spectrum distribution curve of the radiation source under the operating voltage conditions can be obtained through measurement.

[0123] It should be noted that the ray energy spectrum distribution may include a ray energy spectrum distribution curve, but is not limited to this. It may also include a ray energy spectrum distribution dot diagram, etc. The embodiments of the present disclosure do not limit the specific type of ray energy spectrum distribution. Those skilled in the art can design it according to actual needs, as long as it can characterize the distribution of radio frequency energy.

[0124] According to an embodiment of the present disclosure, by calculating the first theoretical intersection line formed in the calibration phantom by the connecting line between the theoretical position of the target and the theoretical position of the detection, the theoretical position of the radiation passing through the calibration phantom can be determined when the target of the radiation source and the detector crystal are respectively at the theoretical positions. Therefore, the first theoretical intersection line, the attenuation coefficient of the radiation in the calibration phantom, and the energy spectrum distribution of the radiation of the radiation source can be used to calculate the first detection projection information used to characterize the situation when the target and the detection crystal are both at the theoretical positions. Then, according to the difference between the second detection projection information obtained by scanning the calibration phantom by the imaging device and the first detection projection information, the parameters of the imaging device are adjusted, thereby The parameters of the imaging device corresponding to the time when the difference between the second detection projection information and the first detection projection information is minimized can be used as the target parameters, thereby completing the calibration of the system parameters of the imaging device, and thus at least partially solving the technical problem in the related art that the operation of the imaging device calibration process is relatively cumbersome and highly dependent on the professional level of the operator. At the same time, the calibration method provided in this embodiment can be repeatedly applied to different CT imaging devices with more complex and diverse system structures. The calibration method for imaging devices provided in the embodiment of the present disclosure can achieve accurate calibration of the CT imaging device, thereby improving the image quality of the reconstructed image output by the CT imaging device.

[0125] According to an embodiment of the present disclosure, the parameters of the imaging device may include: a target position of a radiation source and a detection position of a detector.

[0126] According to the embodiments of the present disclosure, the target position of the radiation source and the detection position of the detector may be the actual coordinate positions of the target position of the radiation source and the detector after the imaging device is assembled. Due to assembly errors and other reasons, the actual coordinate positions may be offset from the theoretical positions, and the directions and distances of the offsets of the actual coordinate positions are difficult to measure. The calibration method provided by the embodiments of the present disclosure can take the difference information between the first detection projection information and the second detection projection information as the optimization target, and then at least adjust the target position of the radiation source and the detection position of the detector so that the target position and the detection position corresponding to the minimized difference information are used as the target parameters of the imaging device, thereby realizing the calibration of the imaging device, and then at least partially solving the technical problem of difficulty in calibrating the imaging device due to assembly errors, abnormal movement and other reasons, improving the calibration accuracy and calibration speed of the imaging device, and realizing improving the imaging effect of the imaging device.

[0127] According to an embodiment of the present disclosure, the calibration phantom is set in the scanning area of ​​the imaging device; and the coverage area of ​​the calibration phantom covering the scanning area is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning area of ​​the scanning area.

[0128] According to an embodiment of the present disclosure, the calibration phantom can be entirely disposed within the scanning area, and the coverage area of ​​the calibration phantom covering the scanning area can be the coverage area of ​​the shape formed by the outermost edge of the calibration phantom occupying the scanning area. When the coverage area of ​​the calibration phantom covering the scanning area is greater than or equal to a preset coverage threshold, for example, when the outermost edge of the calibration phantom coincides with the boundary of the scanning area, and the calibration phantom is entirely disposed within the scanning area, the imaging device can completely scan the calibration phantom, thereby achieving optimal imaging quality for a reconstructed detection image generated by the imaging device after scanning the calibration phantom, thereby avoiding degradation of image quality in local areas of the detection image.

[0129] It should be noted that the shape and structure of the calibration phantom are not limited in the embodiments of the present disclosure. For example, the calibration phantom may be an irregular shape, but is not limited thereto. The calibration phantom may also be a regular shape, such as a cube, etc. Those skilled in the art may make a choice based on actual conditions.

[0130] According to an embodiment of the present disclosure, the calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

[0131] According to an embodiment of the present disclosure, the calibration wire includes at least one of the following: a cylindrical calibration wire, a cubic calibration wire, a conical calibration wire, and a trapezoidal calibration wire.

[0132] FIG2B schematically shows a schematic diagram of a calibration unit and a calibration phantom according to an embodiment of the present disclosure.

[0133] As shown in Figure 2B, the calibration phantom units 210, 220, and 230 may include a plurality of calibration wires 211 distributed in an array. The calibration wires 211 in the calibration phantom units 210, 220, and 230 may be fixed in different ways, that is, the calibration wires may be arranged in different arrays to form the calibration phantom units.

[0134] Furthermore, the calibration phantom 200B may include a calibration phantom unit 210 , so that the calibration phantom 200B includes calibration wires 211 arranged in a matrix, but not limited thereto. The calibration phantom 200C may also include calibration wires distributed in a circular array.

[0135] It should be noted that the shape, structure, arrangement, etc. of the calibration phantom, calibration unit or calibration wire in Figure 2B are all exemplary embodiments and do not limit the specific structural form of the calibration phantom. Those skilled in the art can design a variety of calibration phantoms according to actual needs, for example, by designing a calibration phantom by diversifying the arrangement of the calibration wire.

[0136] According to the embodiments of the present disclosure, a calibration phantom is set up by setting up a plurality of calibration wires distributed in an array, so that a calibration phantom with a regular shape and regular form can be obtained, thereby improving the imaging effect of the detection image obtained after the imaging device scans the calibration phantom, that is, the accuracy and reliability of the second detection position information can be obtained, thereby improving the accuracy of the target parameters generated subsequently, and improving the detection effect of the calibrated imaging device.

[0137] According to an embodiment of the present disclosure, in operation S230, adjusting parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom with the imaging device may include the following operations:

[0138] The difference information between the first detection projection information and the second detection projection information is processed according to the objective function to obtain the target parameters, wherein the imaging device calibrated according to the target parameters converges the target difference information between the target second detection projection information and the first detection projection information obtained after scanning the calibration model.

[0139] According to an embodiment of the present disclosure, the objective function may include an algorithm used in related technologies for fitting difference information, for example, it may include a least squares function, etc. The embodiment of the present disclosure does not limit the specific algorithm type of the objective function, as long as it can be determined that the target difference information between the second detection projection information and the first detection projection information converges.

[0140] According to an embodiment of the present disclosure, the objective function includes a mapping function and a loss function.

[0141] FIG3A schematically shows a flow chart of processing difference information between first detection projection information and second detection projection information according to an objective function to obtain target parameters according to an embodiment of the present disclosure.

[0142] As shown in FIG3A , in this embodiment, processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameter may include operations S310 to S340 .

[0143] In operation S310 , the first detection projection information and the second detection projection information are respectively processed using a mapping function to obtain a first projection mapping value and a second projection mapping value.

[0144] In operation S320 , the first projection mapping value and the second projection mapping value are processed using a loss function to obtain a loss value.

[0145] In operation S330 , parameters of the imaging device are iteratively adjusted according to the loss value until the loss function converges.

[0146] In operation S340 , a parameter corresponding to when the loss function converges is determined as a target parameter.

[0147] According to an embodiment of the present disclosure, the first detection projection information and the second detection projection information can be respectively used as independent variables of the mapping function, that is, the mapping function can be expressed as f(), and the first projection mapping value and the second projection mapping value can be expressed as f(P1) and f(P2), respectively; the difference between the first projection mapping value and the second projection mapping value (that is, the loss value) is used as the optimization target, and the loss value is processed using the loss function to iteratively adjust the parameters of the imaging device until the corresponding parameters when the loss function converges are used as the target parameters, thereby realizing calibration of the imaging device.

[0148] According to an embodiment of the present disclosure, by taking the difference between the first projection mapping value and the second projection mapping value (i.e., the loss value) as the optimization target, the minimum difference between the target parameters of the imaging device and the theoretical position of the imaging device can be determined, thereby improving the generalization ability of the calibration method, enabling the calibration method to adapt to imaging devices with complex components, and improving the calibration efficiency of the imaging device.

[0149] It should be noted that the specific number of times the parameters of the imaging device are iteratively adjusted may be once or multiple times, and the embodiments of the present disclosure do not limit the specific number of times the parameters of the imaging device are adjusted.

[0150] FIG3B schematically shows an application scenario diagram of a calibration method for an imaging device according to another embodiment of the present disclosure.

[0151] FIG3C schematically shows a schematic diagram of an energy spectrum distribution curve of a radiation source according to an embodiment of the present disclosure.

[0152] FIG3D schematically shows a curve diagram of the change in mass attenuation coefficient and X-ray energy of a calibration phantom according to an embodiment of the present disclosure.

[0153] As shown in Figures 3B, 3C, and 3D, the application scenario may include an imaging device 310 and a calibration phantom 320. The imaging device 310 may include a radiation source 311 and a detector 312. The target point of the radiation source 311 may emit a radiation signal, which may be an X-ray, toward the calibration phantom 320. After passing through the calibration phantom 320, the radiation signal may be received by the detector 312, thereby obtaining second detection projection information P2 obtained by the imaging device 310 scanning the calibration phantom 320.

[0154] According to an embodiment of the present disclosure, it can be assumed that the energy spectrum distribution of the ray signal generated by the radiation source 311 remains consistent under the same operating voltage conditions. For example, when the operating voltage of the radiation source 311 is 120 kVp, the generated X-ray signal can be represented by the energy spectrum distribution curve shown in Figure 3C.

[0155] According to an embodiment of the present disclosure, when the calibration phantom 320 is made of PMMA, the linear attenuation coefficient μ of the calibration phantom 320 can be determined. FIG3D shows a curve showing the relationship between the mass attenuation coefficient μ / ρ of the calibration phantom 320 and the energy of the X-ray signal generated by the radiation source 311. Here, ρ represents the density of the cylindrical calibration wire in the calibration phantom 320.

[0156] When the ray energy spectrum distribution curve of the radiation source 311 and the mass attenuation coefficient of the calibration phantom 320 are obtained, the theoretical spatial three-dimensional coordinates of the first theoretical intersection line can be calculated based on the theoretical target position of the radiation source 311, the theoretical detection position of the detector 312, and the phantom position of the calibration phantom, that is, in the coordinate system of the imaging device 310, the theoretical spatial three-dimensional coordinates of the target of the radiation source 311, the theoretical spatial three-dimensional coordinates of the detector pixels of the detector 312, and the spatial three-dimensional coordinates of the calibration phantom 320, so as to determine the propagation path of the X-ray beam inside the calibration phantom 320.

[0157] Then, the first detection projection information P1 can be calculated using formula (1).

[0158] In formula (1), I0 represents the incident intensity of the ray signal when it reaches the surface of the calibration phantom, I represents the exit intensity of the ray signal when it passes through the calibration phantom, E represents the energy of the ray signal, ρ represents the density of the calibration phantom, L represents the length of the first theoretical intersection line, and l represents the length of the material corresponding to the density ρ in the length of the first theoretical intersection line.

[0159] It should be understood that when the material of the calibration phantom 320 is a uniform PMMA material, (E, l) / ρ can be simplified to μ(E) / ρ, and formula (1) can be further simplified to formula (2).

[0160] After obtaining the first detection projection information P1 and the second detection projection information P2, the difference between the first detection projection information P1 and the second detection projection information P2 can be used as an optimization target. By adjusting the parameters of the imaging device 310, the difference can be minimized to obtain the target parameters of the imaging device 310. For example, the method in the above embodiment can be used to determine the target parameters, thereby realizing calibration of the imaging device 310.

[0161] According to an embodiment of the present disclosure, when the material of the calibration phantom is a uniform material, the linear attenuation coefficient of the material can be used to calculate the first detection projection information P1. When the calibration phantom is constructed of different materials, the mass attenuation coefficient of the material can be used to calculate the first detection projection information P1, thereby further improving the adaptability and generalization ability of the calibration method provided in the embodiment of the present disclosure for calibrating imaging devices for different calibration phantoms.

[0162] It should be understood that the imaging device can scan the calibration phantom according to a preset scanning angle interval. The scanning angle interval can be designed according to actual needs. After the imaging device scans the entire scanning area according to the preset scanning angle interval, it can complete one scan to obtain complete second detection projection information for the calibration phantom, that is, the number of second detection projection information can be multiple, and each second detection projection information is associated with the actual coordinate position of the detector crystal that receives the radiation signal.

[0163] It should be noted that when the imaging device 310 in FIG3B is a toroidal CT imaging device (also known as a toroidal CT system) in the related art, the radiation source and the detector are relatively stationary and rotate around the calibration phantom for scanning. In order to more accurately calibrate the imaging device, the second detection projection information obtained after scanning at multiple viewing angles and the first detection projection information corresponding to each viewing angle can be used to increase the amount of data for generating target parameters and improve the calibration effect of the imaging device. In order to obtain a better calibration effect, the scanning angle interval can be further reduced to increase the number of scanning angles, thereby further expanding the amount of data and laying the foundation for the subsequent generation of accurate target parameters.

[0164] According to an embodiment of the present disclosure, the imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2.

[0165] FIG4 schematically illustrates a flow chart for adjusting parameters of an imaging device using first detection projection information and difference information between second detection projection information obtained by scanning a calibration phantom with the imaging device according to an embodiment of the present disclosure.

[0166] As shown in FIG. 4 , in this embodiment, adjusting the parameters of the imaging device using the first detection projection information and the difference information between the second detection projection information obtained by scanning the calibration phantom by the imaging device may include operations S410 to S420 .

[0167] In operation S410, based on the second detection projection information obtained by each scanning-level imaging device scanning the calibration object and the difference information between the first detection projection information corresponding to each scanning-level imaging device, the device imaging parameters of each scanning-level imaging device are adjusted to obtain the calibrated target device imaging parameters of each scanning-level imaging device.

[0168] In operation S420, the target device imaging parameters of the L scanning-stage imaging devices are calibrated to obtain calibrated target parameters.

[0169] According to an embodiment of the present disclosure, each scanning-level imaging device may include a radiation source and a detector, thereby constituting a scanning level of an imaging device. The imaging device may construct a detection image of the detected object based on the projection information obtained after each of the L scanning-level imaging devices scans the detected object.

[0170] According to an embodiment of the present disclosure, according to the respective coordinate systems of each scanning-level imaging device, the imaging parameters of the target device corresponding to each scanning-level imaging device can be obtained, and the imaging parameters of the target device of each of the L scanning-level imaging devices can be calibrated into coordinate system one. For example, the coordinate system one of the L scanning-level imaging devices can be used as the coordinate system of one of the scanning-level imaging devices, and then the imaging parameters of the target device corresponding to each scanning-level imaging device can be calibrated into coordinate system one, thereby realizing convenient calibration of imaging equipment with complex components to improve the calibration efficiency of the imaging equipment.

[0171] According to an embodiment of the present disclosure, the calibration phantom is set in N different calibration areas, where N≥2.

[0172] The calibration method may further include the following operations:

[0173] The calibration phantom in each calibration area is scanned by an imaging device to obtain candidate second detection projection information corresponding to each calibration area; and the second detection projection information is determined according to the candidate second detection projection information corresponding to each of the N calibration areas.

[0174] According to an embodiment of the present disclosure, the second detection projection information may include candidate second detection projection information corresponding to N calibration areas. At the same time, the candidate second detection projection information corresponding to each calibration area may also have an area identifier representing the corresponding calibration area, thereby facilitating the distinction of the calibration areas corresponding to the second detection projection information.

[0175] According to an embodiment of the present disclosure, by setting the calibration phantom in N different calibration areas and then obtaining the first detection projection information and the second detection projection information corresponding to each calibration area, on the one hand, the amount of data used to obtain the target parameters can be increased, and on the other hand, the imaging effect of the detection image of each calibration area of ​​the calibrated imaging device can be improved, thereby improving the imaging effect adjustment of the detection image reconstructed by the imaging device within the range of multiple calibration areas, and then achieving overall adjustment of the imaging effect of the imaging device, avoiding the decline in the scanning imaging effect of the imaging device for the detected objects set in some calibration areas.

[0176] FIG5 schematically shows a flowchart of adjusting parameters of an imaging device by using difference information between first detection projection information and second detection projection information obtained by scanning a calibration phantom with the imaging device according to another embodiment of the present disclosure.

[0177] As shown in FIG. 5 , in this embodiment, adjusting parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom by the imaging device may include operations S510 to S540 .

[0178] In operation S510, the first detection projection information and the second detection projection information are respectively processed using a mapping function to obtain a first projection mapping value and a second projection mapping value, wherein the first detection projection information and the second detection projection information correspond to the same calibration area.

[0179] In operation S520, according to the correspondence between the calibration area and the first detection projection information and the second detection projection information, the first projection mapping value and the second projection mapping value corresponding to each calibration area are processed separately using the loss function to obtain a first loss value set, which includes the first loss value corresponding to each calibration area.

[0180] In operation S530 , parameters of the imaging device are iteratively adjusted according to a first loss value in the first loss value set until the loss function converges.

[0181] In operation S540 , a parameter corresponding to when the loss function converges is determined as a target parameter.

[0182] According to an embodiment of the present disclosure, target parameters may be determined based on a gradient descent algorithm to reduce the difference between the target parameters and theoretical parameters, thereby improving the imaging accuracy of the calibrated imaging device.

[0183] According to an embodiment of the present disclosure, the calibration phantom is set in the calibration area, and the calibration phantom set in the calibration area includes M calibration poses.

[0184] The imaging device calibration method further includes the following operations:

[0185] The calibration phantom of each calibration posture is scanned by an imaging device to obtain candidate second detection projection information corresponding to the calibration phantom and each calibration posture; and the second detection projection information is determined according to the candidate second detection projection information corresponding to each of the M calibration postures.

[0186] According to an embodiment of the present disclosure, the calibration posture may include a setting manner of setting the calibration phantom in the calibration area, and different calibration postures of the calibration phantom may be achieved by flipping, moving, rotating, and the like.

[0187] According to an embodiment of the present disclosure, the second detection projection information may include candidate second detection projection information corresponding to M calibration postures, thereby expanding the data volume of the second detection projection information.

[0188] According to an embodiment of the present disclosure, for a calibration area where the image reconstruction effect needs to be improved, multiple calibration postures can be set for the calibration phantom in the calibration area, thereby increasing the data volume of the first detection projection information and the second detection projection information for the calibration area, so as to enhance the imaging effect of the calibrated imaging device for the calibration area.

[0189] FIG6 schematically shows a flowchart of adjusting parameters of an imaging device by using difference information between first detection projection information and second detection projection information obtained by scanning a calibration phantom with an imaging device according to yet another embodiment of the present disclosure.

[0190] As shown in FIG6 , in this embodiment, adjusting the parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom by the imaging device may include operations S610 to S640 .

[0191] In operation S610, the first detector projection information and the second detector projection information are respectively processed using a mapping function to obtain a first projection mapping value and a second projection mapping value, wherein the first detection projection information and the second detection projection information correspond to the same calibration posture.

[0192] In operation S620, according to the correspondence between the calibration posture and the first detection projection information and the second detection projection information, the first projection mapping value and the second projection mapping value corresponding to each calibration posture are respectively processed using the loss function to obtain a second loss value set, which includes the second loss value corresponding to each calibration posture.

[0193] In operation S630 , parameters of the imaging device are iteratively adjusted according to the second loss value in the second loss value set until the loss function converges.

[0194] In operation S640 , a parameter corresponding to when the loss function converges is determined as a target parameter.

[0195] It should be noted that the first loss value and the second loss value in the embodiment of the present disclosure are only for distinguishing and explaining the corresponding relationship of the loss values, and do not limit the first loss value to correspond to the calibration area, nor do they limit the second loss value to correspond to the calibration posture. Different calibration postures can be set for the calibration phantom in different calibration areas, so as to obtain the loss value corresponding to the calibration phantom with the calibration posture in the calibration area. The loss value can be the first loss value or the second loss value, which is not limited in the embodiment of the present disclosure.

[0196] According to an embodiment of the present disclosure, a multi-view scan can also be performed on a calibration phantom set in a calibration area to obtain first detection projection information and second detection projection information corresponding to each view. Then, based on the difference between the first detection projection information and the second detection projection information corresponding to each view, the target parameters can be determined to complete the calibration of the imaging device.

[0197] It should be understood that the second detection projection information corresponding to each scanning perspective obtained by scanning the calibration phantom from multiple perspectives is similar to scanning the calibration phantom from a single perspective with multiple calibration postures, and the calibration phantom can be scanned from different relative angles.

[0198] Based on the above-mentioned calibration method for an imaging device, the present disclosure further provides a calibration device for an imaging device, which will be described in detail below in conjunction with FIG8 .

[0199] According to the embodiments of the present disclosure, the calibration method of the imaging device provided in the embodiments of the present disclosure can quickly, effectively and accurately obtain the optimal system parameters of the imaging device, that is, the target parameters, so that the calibrated imaging device can reconstruct a detection image with better image effect. At the same time, it can also cooperate with other modules in the imaging device to more accurately carry out tasks such as object recognition, thereby obtaining better practical application effects.

[0200] FIG7 schematically shows a structural block diagram of a calibration apparatus for an imaging device according to an embodiment of the present disclosure.

[0201] As shown in FIG. 7 , the calibration apparatus 700 for an imaging device of this embodiment includes a calculation module 710 , a determination module 720 , and an adjustment module 730 .

[0202] The calculation module 710 is configured to calculate a first theoretical intersection line based on the target theoretical position of the radiation source of the imaging device, the detection theoretical position of the detector, and the phantom position of the calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after the connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom.

[0203] The determination module 720 is configured to determine first detection projection information for the calibration phantom based on the first theoretical intersection line, the attenuation coefficient of the radiation emitted by the radiation source in the calibration phantom, and the energy spectrum distribution of the radiation source in the imaging device.

[0204] The adjustment module 730 is configured to adjust the parameters of the imaging device using the difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom by the imaging device, so as to calibrate the imaging device and obtain the calibrated target parameters.

[0205] According to an embodiment of the present disclosure, the adjustment module may be further configured to:

[0206] The difference information between the first detection projection information and the second detection projection information is processed according to the objective function to obtain the target parameters, wherein the imaging device calibrated according to the target parameters converges the target difference information between the target second detection projection information and the first detection projection information obtained after scanning the calibration model.

[0207] According to an embodiment of the present disclosure, the objective function includes a mapping function and a loss function.

[0208] Processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameters includes:

[0209] The first detection projection information and the second detection projection information are processed respectively by a mapping function to obtain a first projection mapping value and a second projection mapping value; the first projection mapping value and the second projection mapping value are processed by a loss function to obtain a loss value; the parameters of the imaging device are iteratively adjusted according to the loss value until the loss function converges; and the parameters corresponding to the convergence of the loss function are determined as target parameters.

[0210] According to an embodiment of the present disclosure, the adjustment module may include a first processing submodule, a second processing submodule, a first adjustment submodule, and a first determination submodule.

[0211] The first processing submodule is configured to respectively process the first detection projection information and the second detection projection information using a mapping function to obtain a first projection mapping value and a second projection mapping value.

[0212] The second processing submodule is used to process the first projection mapping value and the second projection mapping value using a loss function to obtain a loss value.

[0213] The first adjustment submodule is used to iteratively adjust the parameters of the imaging device according to the loss value until the loss function converges. The first determination submodule is used to determine the parameters corresponding to the convergence of the loss function as target parameters.

[0214] According to an embodiment of the present disclosure, the imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2.

[0215] The adjustment module may further include a second adjustment submodule and a first unification submodule.

[0216] The second adjustment submodule is used to adjust the device imaging parameters of each scanning-level imaging device based on the second detection projection information obtained by each scanning-level imaging device scanning the calibration object and the difference information between the first detection projection information corresponding to each scanning-level imaging device, so as to obtain the target device imaging parameters after calibration of each scanning-level imaging device.

[0217] The first unification submodule is used to coordinate the target device imaging parameters of the L scanning-level imaging devices to obtain calibrated target parameters.

[0218] According to an embodiment of the present disclosure, the calibration phantom is set in N different calibration areas, where N≥2.

[0219] The calibration device also includes: a first scanning module and a first determining module.

[0220] The first scanning module is used to scan the calibration phantom in each calibration area using an imaging device to obtain second detection projection information corresponding to each calibration area.

[0221] The first determining module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the N calibration areas.

[0222] According to an embodiment of the present disclosure, the calibration phantom is set in the calibration area, and the calibration phantom set in the calibration area includes M calibration poses.

[0223] The calibration device also includes: a second scanning module and a second determination module.

[0224] The second scanning module is configured to use an imaging device to scan the calibration phantom of each calibration posture respectively to obtain second detection projection information corresponding to the calibration phantom and each calibration posture.

[0225] The second determination module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the M calibration postures.

[0226] According to an embodiment of the present disclosure, the calibration phantom is set in the scanning area of ​​the imaging device; and the coverage area of ​​the calibration phantom covering the scanning area is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning area of ​​the scanning area.

[0227] According to an embodiment of the present disclosure, the calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

[0228] According to an embodiment of the present disclosure, the calibration wire includes at least one of the following: a cylindrical calibration wire, a cubic calibration wire, a conical calibration wire, and a trapezoidal calibration wire.

[0229] According to an embodiment of the present disclosure, the parameters of the imaging device include: a target position of a radiation source and a detection position of a detector.

[0230] According to an embodiment of the present disclosure, any multiple modules in the calculation module 710, the determination module 720, and the adjustment module 730 can be combined into one module for implementation, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules can be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the calculation module 710, the determination module 720, and the adjustment module 730 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware, and firmware, or in an appropriate combination of any of them. Alternatively, at least one of the calculation module 710, the determination module 720, and the adjustment module 730 can be at least partially implemented as a computer program module, which can perform the corresponding function when the computer program module is executed.

[0231] Based on the above-mentioned calibration method and / or calibration device for an imaging device, an embodiment of the present disclosure further provides an imaging device, which will be described in detail below in conjunction with FIG8 .

[0232] FIG8 schematically shows an application scenario diagram of an imaging device according to an embodiment of the present disclosure.

[0233] As shown in FIG. 8 , the imaging device of this embodiment may include a radiation source 810 , a delivery device 820 , a detector 830 , and a calibration device 840 .

[0234] The radiation source 810 is adapted to emit a radiation beam.

[0235] The conveying device 820 is suitable for conveying the inspected items. A conveying channel is defined above the conveying device, and the calibration phantom is arranged in the conveying channel.

[0236] The detector 830 is adapted to receive a radiation beam that passes through the object being inspected or the calibration phantom.

[0237] The calibration device 840 may include the calibration device in the above embodiment.

[0238] The radiation source 810 and the detector 830 can scan the calibration phantom 850 to obtain second detection projection information of the calibration phantom 850 at multiple calibration positions in the transmission channel, and send the second detection projection information to the calibration device 840. The calibration device 840 can also calculate the first detection projection information based on the theoretical target position of the radiation source 810, the theoretical detection position of the detector 830, the calibration positions of the calibration phantom 850, the linear attenuation coefficient of the calibration phantom, and the radiation energy spectrum distribution curve of the radiation source 810.

[0239] In this way, the first detection projection information and the second detection projection information can be used to calibrate the imaging device, so that after the calibration is completed, the imaging device can detect and image the detected object moving in the conveying device 820 to obtain high-quality detection image information for the detected object.

[0240] FIG9 schematically shows a block diagram of an electronic device suitable for implementing a calibration method for an imaging device according to an embodiment of the present disclosure.

[0241] As shown in Figure 9, the electronic device 900 according to an embodiment of the present disclosure includes a processor 901, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 902 or a program loaded from a storage part 908 into a random access memory (RAM) 903. The processor 901 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or a related chipset and / or a dedicated microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 901 may also include an onboard memory for caching purposes. The processor 901 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0242] The RAM 903 stores various programs and data required for the operation of the electronic device 900. The processor 901, the ROM 902, and the RAM 903 are connected to each other via a bus 904. The processor 901 executes the programs in the ROM 902 and / or the RAM 903 to perform various operations of the method flow according to the embodiment of the present disclosure. It should be noted that the programs may also be stored in one or more memories other than the ROM 902 and the RAM 903. The processor 901 may also execute the programs stored in the one or more memories to perform various operations of the method flow according to the embodiment of the present disclosure.

[0243] According to an embodiment of the present disclosure, the electronic device 900 may further include an input / output (I / O) interface 905, which is also connected to the bus 904. The electronic device 900 may further include one or more of the following components connected to the I / O interface 905: an input portion 906 including a keyboard, a mouse, etc.; an output portion 907 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker; a storage portion 908 including a hard disk, etc.; and a communication portion 909 including a network interface card such as a LAN card or a modem. The communication portion 909 performs communication processing via a network such as the Internet. A drive 910 is also connected to the I / O interface 905 as needed. A removable medium 911, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed in the drive 910 as needed, so that a computer program read therefrom can be installed into the storage portion 908 as needed.

[0244] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments, or may exist independently and not be incorporated into the device / apparatus / system. The computer-readable storage medium carries one or more programs, and when executed, implements the method according to the embodiments of the present disclosure.

[0245] According to an embodiment of the present disclosure, a computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, it may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present disclosure, a computer-readable storage medium may include the ROM 902 and / or RAM 903 described above and / or one or more memories other than ROM 902 and RAM 903.

[0246] The embodiments of the present disclosure also include a computer program product, which includes a computer program containing program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the calibration method provided by the embodiments of the present disclosure.

[0247] The computer program executes the above functions defined in the system / device of the embodiment of the present disclosure when the processor 901 executes the computer program. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0248] In one embodiment, the computer program may be stored on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may be transmitted and distributed in the form of a signal on a network medium, downloaded and installed via the communication portion 909, and / or installed from a removable medium 911. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0249] In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 909, and / or installed from a removable medium 911. When the computer program is executed by the processor 901, the above-described functions defined in the system of the embodiment of the present disclosure are performed. According to the embodiment of the present disclosure, the systems, devices, means, modules, units, etc. described above can be implemented by computer program modules.

[0250] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computer programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, python, "C" or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect via the Internet).

[0251] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the above-mentioned module, program segment, or a part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0252] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure may be combined and / or coupled in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or couplings are intended to fall within the scope of this disclosure.

[0253] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be used in combination to advantage. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A calibration method for an imaging device, comprising: Calculating a first theoretical intersection line based on a target theoretical position of a radiation source of the imaging device, a detection theoretical position of a detector, and a phantom position of a calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after a connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom; determining first detection projection information for the calibration phantom based on the first theoretical intersection line, the attenuation coefficient of the radiation emitted by the radiation source in the calibration phantom, and the energy spectrum distribution of the radiation source in the imaging device; and Utilizing difference information between the first detection projection information and second detection projection information obtained by scanning the calibration phantom by the imaging device, parameters of the imaging device are adjusted to calibrate the imaging device and obtain calibrated target parameters.

2. The calibration method according to claim 1, wherein: Adjusting parameters of the imaging device using difference information between the first detection projection information and second detection projection information obtained by scanning the calibration phantom by the imaging device includes: The target parameters are obtained by processing the difference information between the first detection projection information and the second detection projection information according to the objective function, wherein the target difference information between the target second detection projection information obtained after scanning the calibration phantom by the imaging device that is calibrated according to the target parameters and the first detection projection information converges.

3. The calibration method according to claim 2, wherein: The objective function includes a mapping function and a loss function; Processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameter includes: Using the mapping function to process the first detection projection information and the second detection projection information respectively to obtain a first projection mapping value and a second projection mapping value; Processing the first projection mapping value and the second projection mapping value using the loss function to obtain a loss value; iteratively adjusting parameters of the imaging device according to the loss value until the loss function converges; and The parameter corresponding to the loss function when it converges is determined as the target parameter.

4. The calibration method according to any one of claims 1 to 3, wherein: The imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2; Adjusting parameters of the imaging device using the first detection projection information and difference information between the first detection projection information and the second detection projection information obtained by scanning the calibration phantom by the imaging device includes: Adjusting the device imaging parameters of each scanning-level imaging device based on the difference between the second detection projection information obtained by each scanning-level imaging device scanning the calibration object and the first detection projection information corresponding to each scanning-level imaging device to obtain the target device imaging parameters after calibration of each scanning-level imaging device; and The target device imaging parameters of each of the L scanning-stage imaging devices are calibrated into a coordinate system to obtain calibrated target parameters.

5. The calibration method according to claim 1, wherein: The calibration phantom is set in N different calibration areas, N ≥ 2; The calibration method further includes: Scanning the calibration phantom in each calibration area using the imaging device to obtain candidate second detection projection information corresponding to each calibration area; and The second detection projection information is determined according to the candidate second detection projection information corresponding to each of the N calibration areas.

6. The calibration method according to claim 1, wherein: The calibration phantom is set in a calibration area, and the calibration phantom set in the calibration area includes M calibration postures, M≥2; The imaging device calibration method further includes: Scanning the calibration phantom of each calibration posture using the imaging device to obtain candidate second detection projection information corresponding to the calibration phantom and each calibration posture; as well as The second detection projection information is determined according to the candidate second detection projection information corresponding to each of the M calibration postures.

7. The calibration method according to claim 1, wherein: The calibration phantom is disposed in a scanning area of ​​the imaging device; and The coverage area of ​​the calibration phantom covering the scanning region is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning region area of ​​the scanning region.

8. The calibration method according to claim 1, wherein: The calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

9. The calibration method according to claim 8, wherein: The calibration wire includes at least one of the following: Cylindrical calibration wire, cubic calibration wire, conical calibration wire, trapezoidal calibration wire.

10. The calibration method according to any one of claims 1 to 9, wherein: The parameters of the imaging device include: The target position of the radiation source and the detection position of the detector.

11. A calibration device for an imaging device, comprising: a calculation module configured to calculate a first theoretical intersection line based on a target theoretical position of a radiation source of the imaging device, a detection theoretical position of a detector, and a phantom position of a calibration phantom, wherein the first theoretical intersection line represents a propagation path formed within the calibration phantom after a connecting line between the target theoretical position and the detection theoretical position passes through the calibration phantom; A determination module is configured to determine the determining first detection projection information for the calibration phantom based on an attenuation coefficient of the ray in the calibration phantom and a ray energy spectrum distribution of a radiation source in the imaging device; and The adjustment module is configured to adjust the parameters of the imaging device by using the difference information between the first detection projection information and the second detection projection information obtained by the imaging device scanning the calibration model, so as to calibrate the imaging device and obtain the calibrated target parameters.

12. The calibration device according to claim 11, wherein: The adjustment module is further configured to: The target parameters are obtained by processing the difference information between the first detection projection information and the second detection projection information according to the objective function, wherein the target difference information between the target second detection projection information obtained after scanning the calibration phantom by the imaging device that is calibrated according to the target parameters and the first detection projection information converges.

13. The calibration device according to claim 12, wherein: The objective function includes a mapping function and a loss function; Processing the difference information between the first detection projection information and the second detection projection information according to the objective function to obtain the target parameter includes: Using the mapping function to process the first detection projection information and the second detection projection information respectively to obtain a first projection mapping value and a second projection mapping value; Processing the first projection mapping value and the second projection mapping value using the loss function to obtain a loss value; iteratively adjusting parameters of the imaging device according to the loss value until the loss function converges; and The parameter corresponding to the loss function when it converges is determined as the target parameter.

14. The calibration device according to any one of claims 11 to 13, wherein: The imaging device includes a multi-stage imaging device, and the multi-stage imaging device includes L scanning-stage imaging devices, where L≥2; The adjustment module is further configured to: Adjusting the device imaging parameters of each scanning-stage imaging device based on the difference between the second detection projection information obtained by each scanning-stage imaging device scanning the calibration object and the first detection projection information corresponding to each scanning-stage imaging device, to obtain the target device imaging parameters after calibration of each scanning-stage imaging device; as well as The target device imaging parameters of each of the L scanning-stage imaging devices are calibrated into a coordinate system to obtain calibrated target parameters.

15. The calibration device according to claim 11, wherein: The calibration phantom is set in N different calibration areas, N ≥ 2; The calibration device also includes: a first scanning module, configured to scan the calibration phantom in each calibration area using the imaging device to obtain second detection projection information corresponding to each calibration area; and The first determining module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the N calibration areas.

16. The calibration device according to claim 11, wherein: The calibration phantom is set in the calibration area, and the calibration phantom set in the calibration area includes M calibration postures; The calibration device also includes: a second scanning module configured to scan the calibration phantom of each calibration posture using the imaging device to obtain second detection projection information corresponding to the calibration phantom and each calibration posture; as well as The second determination module is configured to determine the second detection projection information according to the candidate second detection projection information corresponding to each of the M calibration postures.

17. The calibration device according to claim 11, wherein: The calibration phantom is disposed in a scanning area of ​​the imaging device; and The coverage area of ​​the calibration phantom covering the scanning region is greater than or equal to a preset coverage threshold, wherein the preset coverage threshold is determined based on the scanning region area of ​​the scanning region.

18. The calibration device according to claim 11, wherein: The calibration phantom includes a calibration phantom unit, and the calibration phantom unit includes a plurality of calibration wires distributed in an array.

19. The calibration device according to claim 18, wherein: The calibration wire includes at least one of the following: Cylindrical calibration wire, cubic calibration wire, conical calibration wire, trapezoidal calibration wire.

20. The calibration device according to any one of claims 11 to 19, wherein: The parameters of the imaging device include: The target position of the radiation source and the detection position of the detector.

21. An imaging device comprising: a radiation source adapted to emit a radiation beam; A conveying device, adapted to convey the inspected article, wherein a conveying channel is defined above the conveying device, and the calibration phantom is disposed in the conveying channel; a detector adapted to receive a radiation beam passing through the object to be inspected or the calibration phantom; as well as A calibration device according to any one of claims 11 to 20.

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